How can sampling the video signal be more destructive than capturing it? Capturing video samples the signal in the same manner. The difference is capturing follows this with processing whereas sampling just saves the data.

User-friendliness is not relevant here. Nice strawmam (or should I say uman?) argument. Regardless, it's really not hard as long as you know what you're doing. You plug the LDP composite output to a BNC adapter, plug it into the device and go.